The present disclosure relates to medical devices, systems, and methods. In particular, the present disclosure relates to medical devices, systems, and methods for stimulating tissue such as nerves to treat various indications. Indications of interest may include urinary and bowel incontinence, for example. Stimulation devices and therapies for urinary and bowel incontinence are currently available in the marketplace but may be limited in at least some cases.
A sacral nerve stimulator, InterStim II, marketed by Medtronic Inc., of Fridley, Minn., provides therapy for urinary or bowel incontinence through the use of electrical stimulation of the sacral nerve by a long-term active implantable device. The InterStim II implantable generator is large, at 14 cc, and must be implanted in the upper buttock. A long lead wire, 33 cm, must then be tunneled to the stimulation site. The generator typically lasts approximately 4.4 years due to the relatively high duty-cycle stimulation requirement of 16 seconds ON, 8 seconds OFF at an amplitude of 3 V, rate of 14 Hz and pulse width of 210 μs.
InterStim patients undergo an invasive qualification step before the generator is implanted, to verify that the therapy has a high likelihood of success. The qualification step requires the implantation of a temporary electrode connected to a transcutaneous wire that plugs into an external neurostimulator carried by the patient, typically for 3 to 5 days.
PTNS (Percutaneous Tibial Nerve Stimulation), marketed by Uroplasty, Inc, of Minnetonka, Minn., also provides therapy for urinary incontinence through electrical stimulation of the tibial nerve via a percutaneous needle electrode. Electrical stimulation is provided by an external stimulator programmed to delivery therapy for approximately 30 minutes. Initially patient sessions are typically scheduled once per week. Sessions can be scheduled less frequently once effective relief occurs.
Accordingly, there are needs for devices, systems, and methods for stimulation that address one or more of the above drawbacks such as large and uncomfortable implant size, low implant lifespan, invasive qualification steps, and too frequent patient sessions, to name a few.